Spiral tuning dial



Aug. 5, 1952 P. WARE 1 2,605,735

SPIRAL TUNING DIAL Filed March 18, 1948 2 SHEETS-SHEET 1 FIG.1

INVENTOR UFMWM ATTQRHEY Aug. 5, 1952 I P. WARE 05,7

SPIRAL TUNING DIAL Y I" Filed March 18, 1948 Y I 2 SPEETS-rSHEET/INVENTOR. PAUL WARE ATTORNEYS Patented Aug. 5, 1952 Allen N. 1., acorporation of Delaware B. Du Mont Laboratories, Inc Passaic,-

2 Claims. (01. 118-1242) This invention relates to an indicating devicethat is provided with a dial on which markings or calibration points arearranged in the form of a spiral. It will be particularly described andillustrated as it is used as a high frequency radio tuning dial. It isnot restricted to this use, however, being particularly suited for anyuse where it is desirable toindicate the position of a shaft which mayturn a plurality of times between stops.

The invention may be understood from the description in connection withthe accompanying drawings in which:

Fig. 1 is a side View of an illustrative embodiment of the invention.

Fig. 2 isa section along the line A-A of Fig. 1.

Fig. 3 is a plan view of the spiral selector gear.

Fig. 4 is a section along the line 4-4 of Fig. 3.

Fig. 5 shows an illustrative layout of the dial,

and

gear.

Reference character I indicates diagrammatically a support for a tuneror other mechanism of the known sort that is provided with a tuningshaft 2 which is to be rotated. This shaft is turned by means of a knob3. A gear 4, which may, for instance, be made of fibre is secured to theshaft 2 by holder 5. I

Gear 4 meshes with a gear 6 which is attached to a disc 8 which has aspiral groove 8' in one side thereof. Gear 6 and disc 8 are so connectedthat they rotate together on a shaft?! thatis fixed in position. A dial1, which is preferably of material such as Lucite or other lighttransmitting plastic material that can be adapted for edge-lighting, ismounted in front of the gear 6, so that it turns with this gear.

An arm I is supported on shaft l I. This arm ID has a bend l0 in it sothat it does not strike shaft 2 before it is turned sufficiently onshaft H. A pin l3 carrying a roller I3, is mounted on the arm l0 nearthe opposite end of this arm from shaft II. This pin and roller extendinto the spiral groove 8' in disc 8. A spring l2 keeps tension on armIll so that the roller constantly rolls along the outer edge of thegroove 8 in the disc 8.

A block I4 which supports a frame I is mounted on arm Ill. This frame I5is made of lightweight material and is shaped so as to extend upwardlyacross the face of the dial 1. The end of frame I5 is formed into a loopor ring l6,

through which the numerals and markings on the dial 1 may be observed.This loop I6 has radially extending points 11.

An illustrative marked dial is shown in Fig. 5. This particular dial isfor use on a television receiver tuning assembly, and shows the numberedtelevision channels as well as frequency in megacycles for tuning infrequency modulated stations, etc.

Fig. 6 shows a portion, greatly enlarged, of the spiral groove 8' ofdisc 8 in which pin l3 carrying roller I3 is caused by the action ofspring [2 to be tensioned against the outer edge of the groove 8'. AV-shaped notch l8 may be provided into which the roller l3 will'fall,thus causing a noticeable detent action at each of several predeterminedpoints which may correspond to the numbered television channels shown onthe illustrative dial of Fig. 5.

The device is operated by turning the knob 3. When this knob 3 isturned, the dial 1 is turned at a slower rate. As this dial and disc 8are turned, the pin I3 is moved along the spiral groove 8' of disc 8,thus causing the arm [0 to move on shaft H as a-pivot. As the arm Ill.moves it carries the frame [5 with it. The loop or ring I6 which iscarried. by this frame is thus caused to move substantially horizontallyacross the face of the dial 1. Thus the successive portions of this dialthat are visible through the loop 16 are in the form of a spiral. Eachtime a numbered channel appears behind the loop, a detent is felt on theknob, and a click is heard as the roller falls into notch on the spinalgroove. A suitable enclosure, notfshown, with a slightly arcuatehorizontal slot therein, may be used to prevent viewing at one time anyof the dial except that portion that is seen through the loop l6. Thepoints I! aid in reading the positions of the dial. The end of the framel5 may be rectangularly shaped with a small rectangularopeningtherethroughso as to obscure all of the dial except that which isbehind this open- What is claimed is:

1. A radio tuning indicator comprising a rotatable dial rigidly affixedto a rotatable disc in back-to-back relationship, said dial havingparallel planar surfaces and being light conducting uninterruptedlythroughout and to all outer surfaces thereof and having a scale on onesurface thereof, said disc having a spiral groove in the surfacethereof, said scale being formed in a spiral corresponding to saidgroove, a viewing frame having an opening therein adjacent 3 said scaleand being pivotally mounted to move substantially parallel and radiallywith respect to the parallel surfaces of said dial. and a guide memberengaging said spiral groove and rigidly attached to said frame to guidesaid opening in alignment with said scale, said rigidly connected frameand guide member forming a rigid combination which: extends around theedges of said dial and disc.

2. The tuning indicator of claim 1 in which said guide member comprisesa pin havinga roller mounted on an arm and bearing -on.--theside of saidgroove, said groove having notches in the side thereof on whichsaidrollerbear's,

said notches acting as detents and being-aligned.

with markings of said scale, said armbeing spring biased against saidside PAULWARE.

4 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,387,551 Meitner g. Aug. 6, 19211,694,384 Herman Dec. 11, 1928 1,975,675 Antelme- Oct. 2, 1934 2,083,924Scantlebury July 15, 1937 2,144,325 Buchardt Jan. 17, 1939 2,218,987Johannesson et a1. Oct. 22, 1940 2,333,787 I-Iofiman Nov. 9, 19432,400,553 Howar'd May 21, 1946

